Brake valve device



Oct. 2O, 1936.- J. c. MccuNl-z BRAKE VAL-VE DEVICE Filed sept. 19, 19352 sheets-sheet 1 x mm. .wwwwkw Nw www a@ mb @N ww QWQ.

n INVENTOR JOSEPH G MCGUNE- A TTORNE Y.

oct. 2o, 1936.

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Patented Oct. 20, 1936 UNITE-o STATES IPATFEN T FF'CE BRAKE VALVE pEvrcEApplication September 19, 1935, Serial No. 41,264

.14 claims.

rIfhis invention relates 4"to uid pressure Ibrakes, and moreparticularly to a brake valve device 'fora fluid pressure brake.

'The principal object of the 'invention is to 4provide animprovedself-lapping brake Valve-device, having high lsensitivity kandrapidity of faction, and quickly operative iin. response Itomanipulation of the brake yvalve `handle through an application zandrelease zone fto supply or Arelease huid :under pressure to -or Ifromthe brake system,.automatical'ly maintaining the desired pressure as'predetermined by the .position to 'which the handle Yis lmoved.

A further vobject of 'the invention is t'o provide an improved:self-lapping Ybrake valve device.

In the accompanying drawings, Fig. 1 is afdetailed View mainly insection lolf ra lbrake 'Valve device constructed according Ato theinventions; Fig. '2 :is a sectional View of 4a portion of the brakevalve handle quadrant Italien ion 'the line '2*2 of Fig. 1; Fig. 3v is.a fragmentary `plan viewof the cam mechanism showing lthe position foffthe handle relative thereto; and Figs. 4, 5, and=6 are sectional viewstaken on the line -Zl of Fig. 1, showing three stages, respectively, iinthe operation of the brahe `valve :device As shown Vin the drawings,'the brake valve device comprises a Acasing 'l 'hay-ing :opposltelydisposed `application -andrelease portions f|`I and 212, said portionsbeing separated in part by a centrai chamber i3, which communicates onthe one side with `a springrchamber `Io in said application portion and-o-n vthe :opposite side With a similar spring chamber il iin saidrelease portion.

end plate i8 is secured `to (the outer end=of the application portionlil and has a valve chamber 2i) containing a pilot Valve 2 I, the flutedstern 212 of which is movably `'mounted in abushing S23 carried in saidfend plate. A valve seat `24 "is formed on said bushing, 'the pilotvalve bein'g normally urged into engagement with .said seat byfa spring2t. AA flexible diaphragm 2:1, :adapted .to operate the pilot valve 2l,is clamped betweenftheendlplate A'll-8 and a Vring 28, countersunk into:the casing wall yof the :spring chamber I6, saiddiaphragm `forming onthe outer side a pressure .chamber :Sii into which a rounded `vend 3l ofthe yal-ve :stern 1212 `projects to engage the center of :saiddiaphragm. A metering spring 532 is dis-Y posed in the .spring chamberi6 and extends between a folio-Wer 33 which engages 'the inner 'side ofthe :diaphragm .and ya plunger '3l-l vslidably mounted .in said springchamber, `while 'a stop 35 is provided on the `end plate i8 for limitingroutward movement of saiddiaphragm -`by the spring.

Afsupply Valve-piston `36 is slidablymounte'd in a bushing .31 carriedin -the application portion fil, said valve having on one side a chamber3'8 connected through a passage "39 in the end plate 'to the valvechamber 2&0. A spring -4I ldisposed in the Achamber 538 urges rthe valveApiston `into engagement with 1an :annular seat rib vi12 'formed on thebushing "Bil for `controlling communication lbetween a. chamber :l5 and'a chamber #2a within the vseat rib 112, which chamber iis connectedthrough Va. *passage "42 and :a passage '44 1to `the pressure fchamber3D. 'The chamber l"455, zto-Which only the router vseated a-rea 'of thevalve piston is normally exposed, is connected through a passage 46 toa'main'reservoir 411, a Irestricted port -48 Abe ing provided in theValve 'piston 'f36 Vfor connecting the chamber 545 With the chamber A3B.

vinterposed lbetween a ring 419 countersunk in -the outer end of Jtherelease portion i12-and van end plate D secured thereto is a l'flexibledia phragm 252, having on one side a pressure chamber 153 land on theother side the spring chamber 1H., which contains a metering spring 15'4which extends between -a plunger 56 and ai follower 51 engaging saiddiaphragm. The metering spring 541is substantiallyof the same size andcompression value as the metering spring '32. A `pilot valve "58 havingfa fluted stem @6| is mounted in a bushing llill "secured in the -endplate 5l), a seat 63 being formed on the bush-ing `for receiving saidValve. A rounded end 64 is provided on the end "ci the pilot valve 58and is maintained in operative engagement with the diaphragm by -aspring disposed in a chamber 66 and acting against the valve stem 6I,said spring normally urging said valve :away from -the seat l63. Thechamber 66 is open `to the atmosphere through a passage Slidably mountedAina vbusi-ring `68 is a release valve piston B9 having on one side a`chamber I'Il connected through -a passage `T2 Withthe chamber 53. Aspring 'T3 -is disposed -in the chamber Tl for 4urging the Vall-vepiston into. engagement with an annular seat rib x'I4 provided on 'thebushing, the -outer fseatedvarea of said yvalve piston being exposed ltoa chamber T6 which is connected to the passage M and thence 'by Way of apassage T1 to a brake cylinder T3. The valve piston :69 has `arestricted' passage 19 through which vthe chambers lil and T6 areconnected, and the valve piston i6!! is adapted to control communicationYbetween the chamber 16 and an atmospheric exhaust passage 8U whichcommunicates with the area inwardly of thel seat rib 14.

J'ournaled iin the casing lf and disposed'on a medial line between theapplication portion II and the release portion I2, is an operating shaft82, which is adapted to be rotated by means of a handle 83. A cam 84,having opposite cam faces 86 and 87, is secured to the shaft 82 withinthe central chamber I3 in axial alignment with the plungers 34 and 56.The cam face 86 operatively engages the end of an adjustable tappet 88having screw-threaded connection to the plunger 34, while the oppositecam face 87 operatively engages the end of a similar tappet 88 havingscrew-threaded connection to the plunger 56, lock nuts 9| and 92 beingfitted on said tappets 88 and 89, respectively. It will be noted that byreason of the location of the cam 84 between the axially aligned tappets88 and 89, frictional resistance to rotation of the shaft 82 isminimized.

In order that the brake valve device may be employed in a brake systemin which an emergency application of the brakes is effected by reducingthe pressure of fluid in a supplementary or emergency pipe normallycharged with fluid under pressure, a rotary valve is provided in a valvechamber 96, which is formed in the lower part of the casing I8 an-d isconnected to the main reservoir 47 by way of a passage 97 and thepassage 46. The rotary valve is supported by an enlarged end 98 of theoperating shaft 82, being secured thereto by means of a pin 99, and ismaintained in engagement with its seat by the upward pressure of aspring 0| disposed between the shaft end 98 and the bottom of the valvechamber 96.

In operation, with the brake valve device in release position as shownin Figs. 1 and 4 of the drawings, fluid under pressure supplied to themain reservoir 47 in the usual manner flows through the passage 46 tothe chamber 45, and thence through the restricted passage 48 in thevalve piston 36 to the chamber 38, and by way of the passage 39 to valvechamber 20. Fluid at main reservoir pressure is also supplied throughthe passage 97 to the valve chamber 96, and thence through a port |82 inthe rotary valve 95 and a passage |03 to the usual emergency pipe |84,charging said pipe with fluid under pressure.

With the cam 84 in the release position as shown in Fig. 4 of thedrawings the plunger 56 is permitted to move inwardly so that when thespring 54 expands to its full length it is not long enough toy movediaphragm 52 to a position to close the valve 58, and this valve willtherefore be maintained in the open position by the spring 65.

The brake cylinder 78 therefore is open to the atmosphere through thepassages 77 and 44, chamber 76, restricted passage 79, chamber 7|,passage 72, chamber 53, past the pilot valve 58, and through the chamber66 and passage 67.

When it is desired to effect an application of the brakes, the brakevalve handle 83 is moved so as to rotate the shaft 82 and cam 84 in acounterclockwise direction, as viewed in Figs. 4 to 6, the initialmovement turning said members to the position shown in Fig. 5. It willbe noted that the initial contour inclination of the cam face 87 isslightly in advance of that of the cam face 86, so that the movement ofthe cam 84 rst forces the tappet 89 engaging said cam face 81 toward theright, and through the medium of the plunger 56, spring 54, follower 57and diaphragm 52, closes the pilot valve 58, overcoming the pressure ofthe spring 65.

The atmospheric connection from the brake cylinder having thus been cutoff, continued movement of the brake valve handle rotates the shaft 82and cam 84 to a service application position, such as that shown in Fig.6, wherein the cam faces 86 and 87 bear against the tappets 88 and 89respectively, further shifting said tappets in opposite directions. Theoutward movement of the tappet 89 causes the plunger 56 to compress thespring 54, the follower 57 and diaphragm 52 being held stationary by theseated pilot valve 58, while the opposite movement of the tappet 88forces the plunger 34, spring 32, follower 33 and diaphragm 27outwardly, so that said diaphragm unseats the pilot valve 2| and engagesthe stop 35.

With the pilot valve 2| unseated, fluid under pressure is dischargedfrom the connected chambers 20 and 38, past said valve at a relativelyrapid rate, and through chamber 38, passage 44 and passage 77 to thebrake cylinder 78. Since the flow through the restricted passage 48 isslow, the consequent sudden reduction in the pressure in chamber 38permits the valve piston 36 to be move-d away from the seat rib 42, andfluid under pressure is then supplied from the main reservoir 47 throughthe passage 46, chambers 45 and 42a, and passages 43, 44 and 77 to thebrake cylinder 78, effecting a service application of the brakes. At thesame time, fluid under pressure ilows through the passage 44 to thechamber 3| and past the unseated pilot valve 2| to the chambers 20 and38 in the application portion II, and also flows through said passage tothe chamber 76 in the release portion I2 and thence through therestricted passage 79 in the valve piston 69 to the chamber 7|, and byWay of the passage 72 to the chamber 53.

When the pressure of uid in the chamber 30 acting against the diaphragm27 has been increased to a degree suiicient toy overcome the opposingpressure of the spring 32, said diaphragm is moved inwardly, permittingthe spring 26 to close the pilot valve 2|. With the outlet from theconnected chambers 28 and 38 thus closed the fluid pressures on oppositesides of the valve piston 36 are equalized by ow through the restrict-Ied passage 48, and the spring 4| then moves said valve piston to itsseat, cutting off further flow of uid under pressure to the brakecylinder.

Fluid which is supplied to the passage 44 leading to the brake cylinder,also flows to the chamber 76 outwardly of the seat rib 74. Fluidsupplied to the chamber 76 flows through the restricted passage 79 tothe chamber 7| and therefrom by way of the passage 72 to the chamber 53and establishes a pressure in the chambers 53 and 7| substantially equalto the pressure which is established in the brake cylinder. As thepressures on opposite sides of the valve piston 68 are subst-antiallyequal this valve piston will be maintained in engagement with its seatby the spring 73.

Fluid at this pressure in the chamber 53 acting on the diaphragm 52 willnot move the diaphragm 52 against the spring 54 as this spring has beencompressed to a slightly greater degree than the spring 32, and thespring 32 will permit the valve 2| to close and cut off the supply offluid to the brake cylinder before the pressure of the fluid supplied tothe brake cylinder, and to the chamber 53, increases to a value highenough to overcome the spring 54.

If it is desired to reduce brake cylinder pressure to effect a partialrelease of the brakes, the brake valve handle 83 is moved so as torotate the cam 84 in a clockwise direction, as

viewed in Figs. 4 to 6 `of the drawings, thereby 'permitting the Vtappet183 to be shifted to the right under lthe combined vpressures of thefluid acting against the diaphragm 21 and ofthe spring 32, whilepermitting the tappet 89 to be rmoved to the left by the combinedpressures `of `fluid acting against the diaphragmV 52 and of the spring513. The inward movement of the dia phragin 52 permits spring 55 to'unseat the vpilot valve 523, thus venting fluid under pressure at arapid .rate from the connected chambers 53 and li to atmosphere' by wayof chamber 65 and passage di. The sudden reduction oi fluid pressure inthe chamber ii then permits the fluid pressure acting in the chamber 'itto unseat the valve piston 69, whereupon fluid under pressure is quickly`discharged from the brake cylinder 'i3 through 'passages 'il and fili,chamber it, and passage iiil to the atmosphere. Y l

When the pressure of fluid in the chamber 53 has been reducedsufiiciently, the metering spring moves the diaphragm iill and pilotvalve 5t outwardly until said valve engages the seat 53, thereby closingthe outlet from the connected .chambers il and iti so as to permit fluidunder pressure build up said chambers by iiow from the chamber 'llithro-ugh the restricted passage i9, until the spring 'it :is enabled tomove the release valve piston E@ to its seat, thus checking furtherreduction of brake cylinder pressure.

To effect a full release of the brakes, the brake valve handle ismovedto release position, in which the cam permits full convergentmovement of the tappets d8 and 69 and the respecn tive plungers, thusreleasing both metering springs. The pilot valve 5S and the valve pistonare then operated as hereinbeiore described to release huid underpressure from the brake cylinder, except that said pilot valve nowremains unseated, there being no pressure opposing that ci spring b5, sothat a complete reduction of brake cyiinder pressure is eiected,communication from said brake cylinder being maintained open in releaseposition by way of the passages 'l and lid, chamber lli, restrictedpassage lfi in the valve piston chamber ll, passage l?, chamber 53, pastthe unseated pilot valve and thence through chamber te and passage El.lf any iiuid under pressure remains in the bralre cylinder after thevalve piston @Si is moved to its seat by the spring i3 it may escape tothe atmosphere past the pilot valve 58.

It will be apparent that my invention provides a selfdapping brake valvedevice embodying improvements in construction andi, arrangement of theparts, and which is extremely sensitive so as to respond rapidly tomanipulation by the operator for gradually applying andy releasing thebrakes.

While one illustrative embodiment of the invention has been described indetail, it is not my intention to limit its scope to that embodi-V mentor otherwise than by the terms of the appended claims. Y

Having now described my invention, what l claim as new and desire tosecure fby Letters Patent, is: v

l. In a fluid pressure brake, in combination,

a brake cylinder, a brake valve device for Icontrolling the supply ofuid under pressure to and from the brake cylindersaid brake valve devicecomprising a supply valve means operable upon a reduction in the fluidpressure lin a chamber 4'for supplying "fluid under pressure to thelbrake cylinder, a release valve lmeans operable upon a reduction in thefluid :pressure -in lan other chamber for releasing fluid under pressurefrom Vthe brake cylinder, a valve .for venting fluid from said supplyvalverchamber., a spring k*a movable abutment subject to theopposing'pressures of said spring and the brake cylinder or `operatingsaid valve, a valve for venting :fluid from said release valve chamber,=a spring, a movable abutment subject to the opposing pressures nof thelastnamed spring and the brake cylinder for operating the last-namedvalve, and manually operable means for varying the force exerted by saidsprings on said abutments.

2. ln a iiuid pressure brake, a brake cylinder,

and a brake valve device controlling the supply of fluid under pressureto and the release of fluid under pressin'e from the brake cylinder, thebrake valve device comprising a movable abutment subject to the opposingpressures of the fluid sup- -plied to the brake cylinder and of aspring, a valve sub-ject to the opposing pressures of the iiuid in achamber and of the iiuid in a vsupply passage and operative on areduction in the pressure of the fluid` in said chamber to establishcommunication between said supply passage and the brake cylinder, avalve controlled by said abutment and controlling a communicationthrough which fluid may be released from said chamber, a movableabutment subject to the opposing pressures of a spring and of the fluidin a chamber, valve means subject to the opposing pressures of the`fluid in said last named chamber and oi the fluid in the brake cylinderand operative on a reduction in the pressure of the fluid in saidchamber to open a communication through which iiuid may be released fromthe brake cylinder, valve means controlled by said last-named abutmentand controlling a passage through which iiuid may be released from thechamber associated therewith, means to vary the force exerted by saidsprings on said abutments.

3. In a fluid pressure brake, a brake cylinder, and a `brake valvedevice controlling the supply of fluid under pressure to and therelease'of fluid under pressure from the brake cylinder, the brake valvedevice comprising a movable abutment subject to the opposing pressuresof the fluid supplied tothe brake cylinder and of a spring, a Valve subnject to the opposing Ypressures of the lfluid in a chamber and of thefluid in a supply passage and operative on a reduction in the pressureof the fluid in said chamber to establish communication between saidsupply passage and the "brake cylinder, means to supply iiuid to saidchamber at a and common restricted rate, a valve controlled by saidabutment and controlling a communication through which iiuid may bereleased from said chamber, a movable abutment subject to the opposingpressures of a spring and of the fluid in a chamber, valve means subjectto the opposing pressures of the fluid in said last-named vchamber andVoi the fluid in the brake cylinder and operative on a reduction in thepressure of the fluid in said chamber to open a communication throughwhich iiuid may be released from the brake cylinder, valve Vmeanscontrolled by said last-named abutment and controlling a passage`through which fluid may be released from the chamber associatedtherewith, and common means to vary the force exerted by the springs onsaid abutments.

4. ln a fluid pressure brake, a brake cylinder, and a brake valve deviceJcontrolling the supply of fluid under pressure to Vand the Vreleasefo'f Ifluid under pressure from the brake cylinder, the brake valvedevice comprising a movable abutment subject to the opposing pressuresof the fluid supplied to the brake cylinder and of a spring, a valvesubject to the opposing pressures of the fluid in a chamber and of thefluid in a supply passage and operative on a reduction in the pressureof the iiuid in said chamber to establish communication between saidsupply passage and the brake cylinder, means to supply fluid from thesupply passage to said chamber at a restricted rate, a Valve controlledby said abutment and controlling a communication through which fluid maybe released from said chamber, a movable abutment subject to theopposing pressures of a spring and of the fluid in a chamber, valvemeans subject to the opposing pressures of the fluid in said lastnamedchamber and of the fluid in the brake cylinder and operative on areduction in the pressure of the fluid in said chamber to open acommunication through which fluid may be released from the brakecylinder, valve means controlled by said last-named abutment andcontrolling a passage through which fluid may be released from thechamber associated therewith, and common means to vary the force exertedby the springs on said abutments.

5. In a fluid pressure brake, a brake cylinder, and a brake Valve devicecontrolling the supply of fluid under pressure to and the release offluid under pressure from the brake cylinder, the brake valve devicecomprising a movable abutment subject to the opposing pressures of thefluid supplied to the brake cylinder and of a spring, a valve subject tothe opposing pressures of the iluid in a chamber and of the iluid in asupply passage and operative on a reduction in the pressure of the fluidin said chamber to establish communication between said supply passageand the brake cylinder, a valve controlled by said abutment andcontrolling a communication through which fluid may be released fromsaid chamber to the brake cylinder, a movable abutment subject to theopposing pressures of a spring and of the fluid in a chamber, valvemeans subject to the opposing pressures of the fluid in said chamber andof the fluid in the brake cylinder and operative on a reduction in thepressure of the iiuid in said last-named chamber to open a communicationthrough which iiuid may be released from the brake cylinder, Valve meanscontrolled by said last-named abutment and controlling a passage throughwhich fluid may be released from the chamber associated therewith, andcommon means to vary the force exerted by said springs on saidabutments.

6. In a fluid pressure brake, a brake cylinder, and a brake valve devicecontrolling the supply of fluid under pressure to and the release offluid under pressure from the brake cylinder, the brake Valve devicecomprising a movable abutment subject to the opposing pressures of theiluid supplied to the brake cylinder and of a spring, a Valve subject tothe opposing pressures ofthe iluid in a chamber and of the uid in asupply passage and operative on a reduction in the pressure of the fluidin said chamber to establish communication between said supply passageand the brake cylinder, means to supply fluid to said chamber at a givenrate, a valve controlled by said abutment and controlling acommunication through which fluid may be released from said chamber at amore rapid rate than said given rate, a movable abutment subject to theopposing pressures of a spring and of the fluid in a chamber, valvemeans subject to the opposing pressures of the fluid in said chamber andof the fluid in the brake cylinder and operative on a reduction in thepressure of the fluid in said lastnamed chamber to open a communicationthrough which fluid may be released from the brake cylinder, valve meanscontrolled by said last-named abutment and controlling a passage throughwhich fluid may be released from the chamber associated therewith, andcommon means to vary the force exerted by said springs on saidabutments.

'7. In a fluid pressure brake, a brake cylinder, and a brake valvedevice controlling the supply of fluid underI pressure to and therelease of fluid under pressure from the brake cylinder, the brake valvedevice comprising a movable abutment subject to the opposing pressuresof the fluid supplied to the brake cylinder and of a spring, a valvesubject to the opposing pressures of the fluid in a chamber and of thefluid in a supply passage and operative on a reduction in the pressureof the fluid in said chamber to establish communication between saidsupply passage and the brake cylinder, a valve controlled by saidabutment and controlling a communication through which fluid may bereleased from said chamber, a movable abutment subject to the opposingpressures of a spring and of the uid in a chamber, means to supply fluidunder pressure to said last-named chamber from a passage communicatingwith the brake cylinder, valve means subject to the opposing pressuresof the fluid in said chamber and of the fluid in the brake cylinder andoperative on a reduction in the pressure of the fiuid in said last-namedchamber to open a communication through which fluid may be released fromthe brake cylinder, valve means controlled by said last-named abutmentand controlling a passage through which fluid may be released from thechamber associated therewith, and common means to vary the force exertedby said springs on said abutments.

8. In a iluid pressure brake, a brake cylinder, and a brake valve devicecontrolling the supply of fluid under pressure to and the release offluid under pressure from the brake cylinder, the brake valve devicecomprising a movable abutment subject to the opposing pressures of thefluid supplied to the brake cylinder and of a spring, a Valve Subject tothe opposing pressures of the fluid in a chamber and of the fluid in asupply passage and operative on a reduction in the pressure of the fluidin said chamber to establish communication between said supply passageand the brake cylinder, a Valve controlled by said abutment andcontrolling a communication through which fluid may be released fromsaid chamber, a movable abutment subject to the opposing pressures of aspring and of the uid in a chamber, means to supply fluid under pressureat a restricted rate to said last-named chamber from a passagecommunicating with the brake cylinder, valve means subject to theopposing pressures of the fluid in said chamber and of the fluid in thebrake cylinder and operative on a reduction in the pressure of the fluidin said lastnamed chamber to open a communication through which fluidmay be released from the brake cylinder, valve means controlled by saidlast-named abutment and controlling a passage through which fluid may bereleased from the chamber associated therewith, and common on -saidabutments. l c A 9. lIn la fluid 'pressure brake, abrake cylinder,

-and a brake "valve device Vcontrolling vthe supply' of fluid underpressure to and the Arelease of v fluid under pressurevfromthe .brakecylinder, the brake valvedevice comprisinga movable abutment subject tothe opposing'ipressures .of the 4fluid `supplied `to the brake cylinderand of-.a spring, 4a

valve subject to the opposing .pressures of the fluid in a chamber andof *the fluid in a supply passage and operative on a reduction in thepressure ofthe fluid in` said chamber to establish communication between.saiid 'supply-passage and the brake cylinder, a- `valve controlled bysaid abutment Vand controlling a communicationthrough vwhich fluid maybe released from said chamber, a movable abutment subject to theopposing pressures of a spring and of the fluid in a chamber, valvemeans subject to the opposing pressures of the fluid in said chamber andof the fluid in the brake cylinder and operative on a reduction in thepressure of the fluid in said last-named chamber to open a communicationthrough Vwhich fluid may be released vfrom the brake cylinder, and valvemeans controlled by said last-named abutment and controlling a passagethrough which fluid may be released from the chamber associatedtherewith to the atmosphere.

10. In a fluid pressure brake, a brake cylinder, and a brake valvedevice controlling the supply of fluid under pressure to and the releaseof fluid under pressure from the brake cylinder, the brake valve devicecomprising a movable abutment subject to the opposing pressures of thefluid supplied to the brake cylinder and of a spring, a valve subject tothe opposing pressures of the fluid in a chamber and of the fluid in asupply passage and operative on a reduction in the pressure of the fluidin said chamber to establish communication between said supply passageand the brake cylinder, a valve controlled by said abutment andcontrolling a communication through which fluid may be released fromsaid chamber, a movable abutment subject to the opposing pressures of aspring and of the uid in a chamber, means tc supply uid under pressureat a restricted rate to said last-named chamber from ai passagecommunicating with the brake cylinder, valve means subject to theopposing pressures of the fluid in said chamber and of the fluid in thebrake cylinder and operative on a reduction in the pressure of the fluidin said last-named chamber to open a communication through which fluidmay be released from the brake cylinder, and valve means controlled bysaid last-named abutment and controlling a passage through which fluidmay be released from the chamber associated therewith at a more rapidrate than the rate at which fluid is supplied thereto.

11. In a fluid pressure brake, a brake cylinder, and a brake valvedevice controlling the supply of fluid under pressure to and the releaseof iluid under pressure from the brake cylinder, the brake valve devicecomprising a movable abutment subject to the opposing pressures of thefluid supplied to the brake cylinder and of a spring, a valve subject tothe opposing pressures of the fluid in a chamber and of the fluid in asupply passage and operative on a reduction in the pressure of the fluidin said chamber to establish communication between said supply passageand the brakecylinder, a valve controlled by said abutment and operatedto release 'fluid from said chamber on-movement of the labutmentbyV-said-V spring', a' movable abutment'lsubject `to lthe opposingpressures ofi-a' spring and of-etheffluid in `achamber, vvalve `meanssubject to' ther opposing pressures of the fluid-in vsaid chamber'and-ofAthe fluid lin the brake `cylinder and operative on Aa rductionin-the`pressure'of the fluid in said lastnamed `chamber to open aYcommunication through which Afluid may vbe released -fromthebrakefcylinder, valve `means controlled vby said` last-named Aabutment-andf controlling Va passage through 'which lfluid may `be released fromthe chamber associated therewith, 'and `common means )to `vary the forceexerted by said springs onj'sai'd abutments.

i12. iin a iluid :pressure brake, a brakel cylinder,Y

and a brake valve device controlling the supply did under pressure toand the release of fluid under pressure from the brake cylinder, thebrake valve device comprising a movable abutment subject to, theopposing pressures of the fluid supplied toi the brake cylinder and of aspring, a valve subject toi the opposing pressures of the fluid in achamber and of the fluid in a supply passage and operative on areduction in the 'pressure of the fluid in said chamber to establishcommunication between said supply passage and the brake cylinder, avalve controlled by said abutment and controlling a communicationthrough which fluid may be released from said chamber and operated tolcut off the release of fluid from the chamber on movement of theabutment by fluid supplied to the brake cylinder, a movable abutmentsubject to the opposing pressures of a spring and of the fluid in achamber, valve means subject to the opposing pressures of the fluid insaid chamber and of the fluid in the brake cylinder and operative on areduction in the pressure of the fluid in said last-named chamber toopen a communication through which fluid may be releasedV from the brakecylinder, valve means controlled by said last-named abutment andcontrolling a passage through which fluid may be released from thechamber associated therewith, and common means to vary the force exertedby said springs o-n said abutments.

13. In a fluid pressure brake, a brake cylinder, and a brake valvedevice controlling the supply oi fluid under pressure toand the releaseof fluid under pressure from the brake cylinder, the brake valve devicecomprising a movable abutment subject to the opposing pressures of thefluid supplied to the brake cylinder and of a spring, a valve subject tothe opposing pressures of the iluid in a chamber and of the fluid in aSupply passage and operative on a reduction in the pressure of the fluidin said chamber to establish communication between said supply passageand the brake cylinder, a valve controlled by said abutment andcontrolling a communication through which iluid may be released fromsaid chamber, a movable abutment subject to the opposing pressures of aspring and of the fluid in a chamber, valve means subject to theopposing pressuresv of the iluid in Said chamber and of the fluid in thebrake cylinder and operative on a reduction in the pressure of the fluidin said last-named chamber tol open a communication through which fluidmay be released from the brake cylinder, valve means controlled by saidlast-named abutment and operative on movement of said abutment by thespring associated therewith to cut off the release of fluid from saidchamber, and common means to vary the force exerted by the said springson said abutments.

14. In a fluid pressure brake, a brake cylinder, and a brake valvedevice controlling the supply of fluid under pressure to and the releaseof fluid under pressure from the brake cylinder, the brake valve devicecomprising a movable abutment subject to the opposing pressures of thefluid supplied to the brake cylinder and of a spring, a valve subject tothe opposing pressures of the uid in a chamber and of the fluid in thesupply passage and operative on a reduction in the pressure of the fluidin said chamber to establish communication between said supply passageand the brake cylinder, a valve controlled by said abutment andcontrolling a communication through which iluid may be released fromsaid chamber, a movable abutment subject to the opposing pressures of aspring and of the uid in a chamber, valve means subject to the opposingpressures of the iluid in said chamber and of the fluid in the brakecylinder and operative on a reduction in the pressure of the fluid insaid last-named chamber to open a communication through which fluid maybe released from the brake cylinder, valve means controlled by saidlast-named abutment and controlling a passage through which fluid may bereleased from the chamber associated therewith, said valve means beingoperated to release fluid from said chamber on movement of the abutmentby uid in said chamber, and common means to vary the force exerted bysaid springs on said abutments.

JOSEPH C. MCCUNE.

